For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.
James Kraft
It is important to note that in Acts 10:47 that baptism comes after salvation. That the men to be baptized had already received the gift of the Holy Spirit. Ephesians 1:13. So baptism is not necessary for salvation, and has nothing to do with salvation which is all by faith alone in what Jesus did for us on the cross.
All those that have trusted Jesus as the only way of salvation are baptized by the Holy Spirit at the moment of belief. Water baptism adds nothing to salvation by grace. It is an outward expression of a persons faith in Jesus finished work on the cross. Baptism has no power to save anyone.
If baptism would save us, then Jesus died in vain.
Salvation is all by faith, not works, so if you add water baptism to salvation by grace, you are adding works to grace. Salvation is by faith alone in what Jesus did for us on the cross plus nothing. Ephesians 2:8-9 Titus 3:5
Romans 11:6 Salvation is by grace, not works. It can only be one or the other. It can not be both. Salvation is by faith alone that only Jesus blood sacrifice for all sin has been paid for. That we are all sinners and can only be saved by what Jesus did for us on the cross.
Danny Hickman
I don't think baptism symbolizes cleansing from sin. If it does, then Jesus would have skipped it. If the priest washing himself before performing his duties was synonymous with baptism, that would suggest that one baptism isn't enough, since the priest had to observe the washings every time he performed the duties that were referenced in one of the answers here.
Baptism isn't about cleansing; it symbolizes death and resurrection. It symbolizes newness of life. Jesus didn't need cleansing. But he was destined to die in his flesh, and to be raised to a life that never ends; a new life; the life he had with the Father before the foundation of the world (John 17:5). That's the symbolism of his baptism by John the Baptist.
So, where did baptism get its beginning?
That's like asking where did thanking God for our food before we eat it, start. Who was the first to do it? Who told that person or those people to offer a prayer of thaknksgiving to God before eating? It isn't pointed out in scripture anywhere. But we do read where Jesus prayed a prayer of thanksgiving to God before feeding masses of people with just a small amount of food. It doesn't, however, say it was the origin of the practice.
Jesus' baptism was the first of its kind. All other baptisms were a shadow. When Jesus emerged from the baptismal pool, the Spirit of God alighted upon him. That's what true baptism is. It is the baptism of the Holy Spirit. It began on that day. It had never happened before.
Danny Hickman
I think Peter explained the meaning that baptism is designed to provide. He called it an antitype; that is, a foreshadowing of something. It's an indication of something that will happen in the future.
According to Peter, Noah's flood was a foreshadowing. Eight people were saved by what killed everybody else on the earth; water. Those eight people weren't cleansed by the flood waters; the flood waters provided them with a means to be saved from death. But without the ark, the water would have killed them too. So their salvation wasn't due to the water, but due to the ark that was in the water.
Peter says that God was patient while the ark was being prepared, "In which a few, that is, eight souls, were saved through water." (1 Peter 3:20).
Here's the part of Peter's explanation that is a little murky: he recounts how Jesus suffered and died, "the just for the unjust." He was put to death in the flesh, but made alive in the Spirit, "by whom He went and preached to spirits in prison... (when?) when once the Divine longsuffering waited..." and eight people were saved.
When did this preaching take place? While Jesus was dead in flesh and alive in spirit for three days? Or does Peter mean that Jesus preached to those spirits in prison while the ark was being prepared for salvation during the flood?
He means that salvation was preached, NOT OFFERED, but proclaimed!
God saved those 8 souls, not the water. Jesus' death and resurrection (baptism) saves us, not ours.